Yes, Shannon Heritage are withdrawing from managing quite a number of tourist attractions...... not just around Dublin, but also in the west - Bunratty Castle & Folk Park, for example. Since Clare Co. Council are directly taking THAT over, the likelihood is that Fingal Co Council will take over Malahide Castle, the Model Railway Museum, Newbridge House in Donabate and so on - I would guess.
Fingal CoCo are the owners. But as a local authority, it is better for them to sub-contract the day-to-day running of anything they can; but museums across the board rarely if ever cover their costs, let alone make a surplus, so as a general rule it isn't easy to find groups to operate such things.
Voluntary society, anyone?